Void fraction measurement of gas-liquid two-phase flow with a 12-electrode contactless resistivity array sensor under different excitation patterns

This work focuses on the void fraction measurement of gas–liquid two-phase flow by a 12-electrode contactless resistivity array sensor. Such a sensor, which can realize different excitation patterns, is developed here. Five different excitation patterns (with 1, 2, 3, 4 or 5 electrodes) and three two-phase distributions (bubble flow, stratified flow and annular flow) are investigated. Two data processing approaches, the data average method and the principal component regression (PCR) method, are used to establish models of void fraction measurement and hence to implement it. Experiments on void fraction measurement are carried out with the 12-electrode contactless resistivity array sensor. The results show that the void fraction measurement performances are different under different excitation patterns. Among the five different excitation patterns studied, the one with five electrodes has the best performance and the absolute values of void fraction measurement errors of the three two-phase distributions are all less than 5.0% (using the data average method) and 3.0% (using the PCR method). Research results indicate that the 5-electrode excitation pattern + PCR combination is a new effective way to implement void fraction measurement of gas–liquid two-phase flow with the 12-electrode contactless resistivity array sensor.<br/

Electrical Impedance Tomography: From the Traditional Design to the Novel Frontier of Wearables

Electrical impedance tomography (EIT) is a medical imaging technique based on the injection of a current or voltage pattern through electrodes on the skin of the patient, and on the reconstruction of the internal conductivity distribution from the voltages collected by the electrodes. Compared to other imaging techniques, EIT shows significant advantages: it does not use ionizing radiation, is non-invasive and is characterized by high temporal resolution. Moreover, its low cost and high portability make it suitable for real-time, bedside monitoring. However, EIT is also characterized by some technical limitations that cause poor spatial resolution. The possibility to design wearable devices based on EIT has recently given a boost to this technology. In this paper we reviewed EIT physical principles, hardware design and major clinical applications, from the classical to a wearable setup. A wireless and wearable EIT system seems a promising frontier of this technology, as it can both facilitate making clinical measurements and open novel scenarios to EIT systems, such as home monitoring

Advances in High-Resolution Microscale Impedance Sensors

Sensors based on impedance transduction have been well consolidated in the industry for decades. Today, the downscaling of the size of sensing elements to micrometric and submicrometric dimensions is enabled by the diffusion of lithographic processes and fostered by the convergence of complementary disciplines such as microelectronics, photonics, biology, electrochemistry, and material science, all focusing on energy and information manipulation at the micro- and nanoscale. Although such a miniaturization trend is pivotal in supporting the pervasiveness of sensors (in the context of mass deployment paradigms such as smart city, home and body monitoring networks, and Internet of Things), it also presents new challenges for the detection electronics, reaching the zeptoFarad domain. In this tutorial review, a selection of examples is illustrated with the purpose of distilling key indications and guidelines for the design of high-resolution impedance readout circuits and sensors. The applications span from biological cells to inertial and ultrasonic MEMS sensors, environmental monitoring, and integrated photonics

Contactless Test Access Mechanism for 3D IC

3D IC integration presents many advantages over the current 2D IC integration. It has the potential to reduce the power consumption and the physical size while supporting higher bandwidth and processing speed. Through Silicon Via’s (TSVs) are vertical interconnects between different layers of 3D ICs with a typical 5μm diameter and 50μm length. To test a 3D IC, an access mechanism is needed to apply test vectors to TSVs and observe their responses. However, TSVs are too small for access by current wafer probes and direct TSV probing may affect their physical integrity. In addition, the probe needles for direct TSV probing must be cleaned or replaced frequently. Contactless probing method resolves most of the TSV probing problems and can be employed for small-pitch TSVs. In this dissertation, contactless test access mechanisms for 3D IC have been explored using capacitive and inductive coupling techniques. Circuit models for capacitive and inductive communication links are extracted using 3D full-wave simulations and then circuit level simulations are carried out using Advanced Design System (ADS) design environment to verify the results. The effects of cross-talk and misalignment on the communication link have been investigated. A contactless TSV probing method using capacitive coupling is proposed and simulated. A prototype was fabricated using TSMC 65nm CMOS technology to verify the proposed method. The measurement results on the fabricated prototype show that this TSV probing scheme presents -55dB insertion loss at 1GHz frequency and maintains higher than 35dB signal-to-noise ratio within 5µm distance. A microscale contactless probe based on the principle of resonant inductive coupling has also been designed and simulated. Experimental measurements on a prototype fabricated in TSMC 65nm CMOS technology indicate that the data signal on the TSV can be reconstructed when the distance between the TSV and the probe remains less than 15µm

Selected Papers from the 9th World Congress on Industrial Process Tomography

Industrial process tomography (IPT) is becoming an important tool for Industry 4.0. It consists of multidimensional sensor technologies and methods that aim to provide unparalleled internal information on industrial processes used in many sectors. This book showcases a selection of papers at the forefront of the latest developments in such technologies

Sensor-based management systems based on RFID technology

Παρατηρήσεις έκδοσης: λείπουν οι σελίδες 78, 102 από το φυσικό τεκμήριο.In this diploma thesis, the RFID technology is analyzed (operating principles, readers' and tags hardware, coding, modulation, anticollision procedures, frequencies, standards, applications). Moreover, a protocol to synchronize readers working in a multi-reader multi-tag environment is proposed. The protocol is applied to the store shelf scanning application and further refined to meet the requirements of this specific application

Integrated Readout at the Quantum-Classical Interface of Semiconductor Qubits

Quantum computing promises to deliver uniquely powerful information processing machines by exploiting the quantum phenomena of superposition and entanglement. In solid-state systems, there has been significant progress in the isolation and control of the fundamental units needed to build such machines, known as qubits. However, scaling-up the number of qubits to the point where sophisticated algorithms can be performed presents considerable experimental challenges. In particular, it is becoming increasingly apparent that a new class of tools will be required to interface between fragile quantum systems, and the classical readout and control hardware of the outside world. This thesis presents experimental investigations towards the development of a scalable readout architecture for semiconductor qubit platforms. Fast readout of a GaAs-AlGaAs double quantum dot in the few-electron regime is first demonstrated via an embedded dispersive gate sensor (DGS), alleviating the burden of requiring separate charge sensors for every qubit. The sensitivity and bandwidth of this technique are extracted and benchmarked against well-established readout methods. Dispersive gate sensing of quantum point contacts (QPCs) is then presented, probing charge rearrangement within the local electrostatic environment of quasi one-dimensional channels. A low-loss, lumped-element, LC resonant circuit is also implemented for frequency multiplexed readout. The second set of experiments concern the design and characterisation of miniaturised, on-chip circulators based on the quantum Hall effect, and the quantum anomalous Hall effect. Microwaves are first capacitively coupled into edge magnetoplasmon modes in a mesoscopic GaAs-AlGaAs droplet. Non-reciprocal forward transmission comparable to off-the-shelf components is observed, which is accounted for within an interferometric picture. This circulator design is then extended to thin films of the three-dimensional topological insulator, Cr-doped (Bi,Sb)2Te3, wherein similar non-reciprocity is demonstrated in the absence of an external magnetic field

An analysis of the fundamental constraints on low cost passive radio-frequency identification system design

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.Includes bibliographical references (leaves 110-115).Passive radio frequency identification (RFID) systems provide an automatic means to inexpensively, accurately, and flexibly capture information. In combination with the Internet, which allows immediate accessibility and delivery of information, passive RFID systems will allow for increased productivities and efficiencies in every segment of the global supply chain. However, the necessary widespread adoption can only be achieved through improvements in performance - including range, speed, integrity, and compatibility - and in particular, decreases in cost. Designers of systems and standards must fully understand and optimize based on the fundamental constraints on passive RFID systems, which include electromagnetics, communications, regulations, and the limits of physical implementation. In this thesis, I present and analyze these fundamental constraints and their associated trade-offs in view of the important application and configuration dependant specifications.by Tom Ahlkvist Scharfeld.S.M